Lee de Forest

Lee de Forest (1873–1961) was an American inventor whose Audion vacuum tube amplified electrical signals and helped make radio broadcasting practical.

Audion: A three-electrode vacuum tube invented by Lee de Forest that could detect and amplify electrical signals. De Forest’s signature invention became the basis of his claim to radio’s electronic age.
Radio broadcasting: The transmission of audio or other programming from a station to a dispersed audience by radio. Audion amplification helped make radio signals strong enough for practical transmission and reception.
Nikola Tesla: A Serbian-American inventor and electrical engineer known for work on alternating-current systems and radio technology. Tesla’s radio patents became part of the legal battles over wireless invention.
University of Chicago: A private research university in Chicago, Illinois, founded in 1890. De Forest earned his doctorate in physics there before beginning his career as an inventor.
Crystal radio receiver: A simple radio receiver that detects signals with a crystal semiconductor and requires no external power. Unlike the Audion, crystal receivers detected signals without electronic amplification.
Vacuum tube: An electronic device that controls current through a vacuum between electrodes. The Audion was an early vacuum tube with an added control electrode.
Reginald Fessenden: A Canadian-born inventor who pioneered continuous-wave radio and early voice and music broadcasts. Fessenden’s work showed the kind of audio transmission that amplification could support.
John Ambrose Fleming: A British electrical engineer who invented the two-electrode Fleming valve for detecting radio signals. Fleming sued De Forest over the Audion’s relationship to his earlier valve.
Wireless telegraphy: The transmission of telegraph signals without wires, chiefly by electromagnetic waves. De Forest entered a field already shaped by wireless telegraphy and sought to improve its receivers.
Spark-gap transmitter: A radio transmitter that generates waves through electrical sparks, producing damped oscillations. De Forest’s tube-based radio technology offered an alternative to the spark transmitters common in early wireless.

Linked from 10 pages